IL-17 family cytokines such as IL-17 (aka IL-17A), the closely related IL-17F, IL-17C and IL-25 have been implicated in the pathogenesis of various inflammatory and autoimmune diseases. In order to devise strategies to disable signaling by these cytokines in diseases, it is imperative to understand the pathways and molecular mechanisms by which these cytokines transmit signals in target cells to effect gene expression. In the past we have cloned an adaptor protein (CIKS) and demonstrated that this protein is absolutely required for signaling by IL-17 family cytokines and their pathogenic effects in disease contexts. Previously we also identified a critical N-terminal domain within the CIKS adaptor protein that mediates a functionally relevant interaction with Traf6, which is required in turn for activation of the NF-kappaB transcription factor, an important downstream effector of IL-17-induced expression. In FY 2013 we have begun to investigate potential roles of other transcription factors in IL-17 cytokines signaling that are known to help control inflammatory responses. In FY 2013 we have also begun to assess whether CIKS-mediated signaling can play a role apart from its obligate role in signaling by IL-17 cytokines. Initial collaborative studies have suggested a possible role of CIKS in responses to reactive oxygen species in some cell types. We are now developing a biologic approach to investigate this in greater depth. In FY2013 we have begun to devise assays to allow for high-throughput screening of agents that may interfere with signaling by IL-17 cytokines.